1. Field of the Invention
This invention relates to a rubber component for a gas cigarette lighter, multi-purpose lighter or other fire-lighting device that vaporizes fuel gas stored in a fuel tank and burns the vaporized gas as it is jetted from a jetting nozzle, particularly to such a rubber component disposed in the fuel supply passage between the fuel tank and the jetting nozzle where it is in contact with the fuel gas.
2. Description of the Related Art
In a gas cigarette lighter, multi-purpose lighter or other such fire-lighting device, particularly in an internal combustion (premixed combustion system) fire-lighting device that effects ignition and burning after premixing air with the fuel gas jetted from the jetting nozzle, the jetting port of the jetting nozzle is made very small (diameter: 50-100 .mu.m) in order to jet gas at a high flow rate. Since the jetting port is therefore easily clogged by foreign matter, problems such as lighting (ignition) failure tend to occur because of insufficient gas jetting.
For overcoming this drawback, Japanese Utility Model Publication 5(1993)-18609 teaches a technique of installing a metal mesh, filter or the like upstream of the jetting nozzle or at the primary air intake so as to catch dust or other foreign matter before it can adhere to and clog the jetting nozzle.
The installation of such a metal mesh or filter does not, however, completely prevent the problem of lighting failure owing to clogging of the jetting nozzle.
To determine the specific reason for this, a fire-lighting device that experienced nozzle clogging was disassembled and the foreign matter adhering to the jetting nozzle was analyzed. The analysis revealed the presence of dioctyl phthalate (DOP). DOP is a highly viscous substance commonly blended with rubber materials as a plasticizer and is generally contained in the O-rings, valve rubber and other rubber seal members used in a fire-lighting device.
When such rubber seal members come in contact with the fuel gas, DOP contained therein is eluted into the gas. Tests showed that when the fuel gas is jetted from the jetting nozzle to be burned, the gas pressure drives the eluted matter up to the jetting nozzle, where it adheres to and clogs the nozzle portion. Since the eluted DOP is in the form of a viscous liquid, the gas pressure can force some of it even through a metal mesh, filter or the like installed in the fuel gas passage. It can therefore reach the region of the jetting nozzle, where it adheres strongly owing to its high viscosity. The adhering DOP is not blown entirely away by the jetted gas but accumulates as an oily mass to obstruct jetting of the gas. It also catches ambient dust and foreign particles that further clog the jetting nozzle. As such, it is a cause of lighting failure.
This plasticizer (DOP) causes problems not only in the internal combustion type fire-lighting device. Also in the ordinary fire-lighting device that does not premix primary air, it similarly obstructs gas supply and causes lighting failure by clogging the flow splitter for improving lighting performance. In any type of fire-lighting device, the plasticizer is liable to make the gas supply rate unstable by finding its way into the flow rate regulation filter.
In light of the foregoing problems, this invention aims to provide a rubber component for a fire-lighting device that prevents obstruction of fuel supply owing to clogging caused by elution of DOP or other such plasticizer from a rubber component disposed in the fuel gas supply passage.